Arsenal boss Arsene Wenger insisted the Premier League remains his top priority after the Gunners thumped Leyton Orient 5-0 in the FA Cup.Orient secured a lucrative fifth-round replay at the Emirates thanks to a last-gasp equaliser in their opening tie, but a Nicklas Bendtner hat-trick and goals to Maroune Chamakh and Gael Clichy ensured there would be no such fairytale on Wednesday.Arsenal advance to a thrilling showdown at Manchester United in the quarter-finals, but with leaders United a mere four points away on the Premier League table Wenger said the Gunners were focused on the top-flight silverware this season."The league is a vital race. For us, the most important one," Wenger said."It will be interesting until the end of the season. Every game now is a cup game - we had one tonight, and will have one on Saturday (against Sunderland).""The race is tight, exciting. I don't rule out Chelsea or Manchester City because everybody can drop points everywhere. If we maintain our consistency we have a very good chance."Arsenal let slip the Carling Cup trophy with a 2-1 loss to Birmingham City in Sunday's final at Wembley, and Wenger was pleased to see his charges return to their winning ways so convincingly."It was a good response, we took the game in a serious way. It was good to win the game," he said."We are in a fantastic run. On Sunday we lost a game in special circumstances."Orient boss Russell Slade praised Arsenal for ruthlessly responding to their 1-1 draw in the reverse fixture."It was a difficult night for us. Chances were few and far between," Slade said."Arsenal were in the mood tonight and made life difficult for us. They played some wonderful football and we tried to live with that.""They are a group of internationals who are very focused and disciplined and their attitude tonight was spot-on."